SU1012987A1 - Method of automatic control of ventilated mill - Google Patents

Abstract

A METHOD FOR AUTOMATIC UNDERING OF A VENTILATED MILL, including measuring the degree of mill load, raw material consumption, finished product yield, and energy carrier temperature and changing the source material feed, depending on the yield of the finished product, characterized in that, in order to improve the control accuracy, the feed is changed energy at given time intervals and determine the difference between the flow rate of the source material and the yield of the finished product, and the change in the supply of energy to the mill depending on the product of the difference between the flow rates; material and the yield of the finished product to the degree of loading of the mill and in proportion to the temperature of the energy carrier. (Lk) so oo

Description

The invention relates to the control of grinding processes in mills ventilated with a stream of transport drying agent, and can be used in the building materials industry, the mining industry and other sectors where the grinding process is combined with the process of drying raw materials by sucking energy through a mill.

There is a known method for automatically controlling the grinding and separation process in a counter-current jet mill, which includes measuring the flow rate of the source material, the temperature of the energy carrier and the dilution, where, in order to find maximum performance, air flow through the mill ij is affected.

The disadvantage of this method is the presence of large fluctuations in the parameters of the dilution and temperature of the air mixture at the time of impact on the flow rate of air, which, in addition, leads to additional fuel consumption.

The closest to the proposed technical essence is a method for automatically controlling the loading of a ventilated mill, which includes measuring the degree of loading of the mill, the consumption of the starting material, the yield of the finished product and the temperature of the energy carrier, and the change in the supply of the starting material depending on the yield of the finished product. In this method, the signal values proportional to the output of the finished product and the air mixture temperature behind the mill are multiplied by the corresponding gain factors for small and significant changes in parameters, thus achieving a higher degree of stabilization of the operating parameters of the mill f 2.

The disadvantage of this method is the difficulty of determining the corresponding coefficients in conditions of significant fluctuations of interrelated parameters characterizing the operation of the mill, which reduces the accuracy of the adjustment.

In addition, the main disturbances affecting the change in the operating parameters of the mill are primarily related to c. a complex indicator: the amount of the source material (raw material) loaded during a certain time and its corresponding average moisture content over this interval.

In the known method of automatic control of valves by mill mills, the adjustment of the mill operation parameters was carried out without the participation of this complex indicator, which leads to instability of the thermal regime of the mill and an increase in fuel consumption. At the same time, the stabilization of the thermal regime of the mill under the conditions of

The variability of the source material is a complex technical problem.

The aim of the invention is to improve the accuracy of regulation.

This goal is achieved in that according to the method of automatic control of a ventilated mill, including measuring the degree of loading of the mill, the flow rate of the source material, the yield of the finished product, the temperature of the energy carrier and the change in the supply of the source material depending on the yield of the finished product, change the supply of energy carrier at predetermined time intervals and determine the difference between the flow rate of the source material and the yield of the finished product, and the change in the supply of energy to the mill is carried out depending on produce a difference between the costs of the original

of the material and the yield of the finished product to the degree of loading of the mill and proportional to the temperature of the energy carrier.

In each time interval, a correspondence is automatically established between the complex value (the product of the quantity of raw material loaded into the mill and its moisture content) and the quantity supplied to the mill.

energy mill prn preset temperature of the latter.

I Moreover, the obtained value of the control signal can also be used to regulate the fuel supply with the same effect of its economy.

The drawing shows a diagram of the device that implements the proposed method.

Using the measuring unit 1, the amount of raw material loaded by the feeder 2 into the mill 3 is continuously recorded. The output signal of the measuring unit 1 is fed to the input of the integrator 4. The current output value of the finished product, formed by measuring unit 5, is associated with a precipitation cyclone system and a gas cleaning unit 6, is fed to the input of the second integrator 7. The control inputs of the integrators 4 and 7 are connected to the interval setting unit 8.

 integrators 4 and 7 are connected to the input of subtraction unit 9, the output of which is connected to one of the inputs of multiplication unit 10. The second input of the multiplication unit 10 is supplied with a signal from the output of the measuring unit 11, to the master load of the mill 3. The second output of the integrator 7 is connected to the controller 12 of the speed of the feeder 2.

The output of the multiplication unit 10 is connected to the control input of the regulator 13, the output of which is connected to the input of the executive body 14 of the fuel supply.

The input of the transmitter 15 is connected to a thermocouple 16, and its input is connected to the correction input of the regulator 13.

The method is carried out as follows.

From measuring blocks 1 and 5 signals, proportional to the amount of raw material loaded into the mill 3 and the finished product yield ,; respectively, are fed to the integrators 4 and 7, where they are integrated until the signal appears at the output of the interval setting block 8.

The 8th arrival point of this signal, the contents of the integrators 4 and 7 are fed to the inputs of the subtraction unit 9, where the integrator 7 signal is subtracted from the integrator 4 signal. Integrators

4 and 7 are set to the zero state and a new integration cycle begins.

The signal from the output of block 9 subtraction. applied to one of the inputs of the multiplication unit 10, where this signal is multiplied by a signal proportional to the degree of loading of the mill 3, received from the measuring unit 11,

The signal from the output of multiplication unit 10 is fed to the input of the regulator 13, which controls the flow of fuel through the executive unit 14. The actual temperature supplied to the energy carrier mill 3 is measured by a thermocouple 16 and through a measuring device. The generator 15, a signal proportional to this temperature, is fed to the correction input of the regulator 13. The duration of the intervals of block 8 is set in accordance with the transition time in mill 3.

When performing subtraction in a block

9, a signal is obtained that corresponds to the difference between the amount of raw material loaded into the mill and the amount of the finished product obtained in the system of precipitation cyclones and the gas cleaning plant b, i.e. value, proportional to the moisture of the raw material.

When performing an operation of multiply, no signal proportional to the degree of loading of the mill 3 (formed by measuring unit 11), and a signal from the output of the subtraction unit, the output of multiplication unit 10 produces a signal proportional to the complex value characterizing the amount of raw material loaded into the mill

5 considering its humidity. This value is proportional to the amount needed to maintain the grinding and drying of raw materials in the mill, in a given time interval.

0

The use of a complex signal to regulate the supply of energy provides the supply of the latter in strict accordance with the need, regardless of any such disturbing influences, which provides significant fuel savings. . .

In addition, using the proposed method ensures reliable stabilization of the thermal regime of the mill and, as a result, improves the quality of the finished product.

Conducted tests on five Aerofol mills showed

5 that control using the proposed method provides fuel savings of 10 to 18%, which makes it possible to obtain an annual economic effect on these mills

0 far more than 34834 rub.

The application of the proposed Method in the construction materials industry (where about 200 ventilated mills are used) allows for a total economic effect of about 1.4 million rubles.

Claims (1)

METHOD FOR AUTOMATIC CONTROL OF A VENTED MILL, including measuring the degree of loading of the mill, the flow rate of the starting material, the yield of the finished product, and the temperature of the energy carrier and changing the supply of the starting material depending on the yield of the finished product, characterized in that, in order to increase the accuracy of regulation, they change the feed energy carrier at predetermined time intervals and determine the difference between the flow rate of the starting material and the finished product yield, and the change in the energy supply to the mill is carried out tvlyayut depending on the product of the difference between the flow rate is ancestral th material and yield the finished product on the degree of loading and proportional to the temperature melnitsy_ energy gonositelya g.